Step-ramp v-hull

ABSTRACT

A boat hull construction provided with longitudinally extending bottom surfaces including (1) a forward section extending generally horizontally forward from generally amidships and curving forwardly and upwardly at its forward end, (2) a generally horizontally disposed rear section spaced rearwardly of the forward section and above a horizontal plane containing the rearmost portions of the forward section, and (3) an intermediate section inclined rearwardly and upwardly and extending between the rear and front ends of the front and rear sections, respectively, a step of low vertical height joining the front and rear ends of the intermediate and forward sections.

0 United States Patent l 13,568,617

[72] Inventor John V. Yost 3,339,514 9/1967 Skuce 1 14/665- 2233 Riverside Drive Trenton Mich Primary Examiner-Andrew H. Farrell 1 pp NQ 6 Attorneys-Clarence A. OBrien and Harvey B. Jacobson [22] Filed Mar. 11,1969 [45] Patented Mar. 9, 1971 ABSTRACT: A boat hull construction provided with longitu- 54 1 STEPJAMP HULL dinally extending bottom surfaces including (1) a forward sec- 7 Claims Drawing a tron extending generally horizontally forward from generally amidships and curving forwardly and upwardly at its forward [52] US. Cl. l l4/66.5 end, 2) a generally horizontally disposed rear section spaced llllt t B635 1/20 rearwardly of the forward section and above a horizontal of l plane containing the earmost portions of the forward section 5 and (3) an intermediate section inclined rearwardly and upwardly and extending between the rear and front ends of the [56] References (med front and rear sections, respectively, a step of low vertical UNITED STATES PATENTS height joining the front and rear ends of the intermediate and 3,160,134 12/1964 Hillman et al. 1 14/665 forward sections.

PATENTED MAR 9:971

sum 1 0F 2 sitar-units v-iiuri.

The hull of the instant invention has been designed to provide smooth riding characteristics, ease of control and low drag at high speeds. The hull is hereinafter described and illustrated in an elongated form suitable for use as a pontoon for a seaplane aircraft or as a pontoon for catamaran-type high speed houseboats and racing catamarans. However, by

foreshortening the hull and increasing its beam-to-length ratio it may be used as a hull for any high speed pleasure craft.

it has long been known that placing a step or series of steps in a boat hull reduces drag by lifting a large section of the hull above the water. This allows higher speeds and more economical operation due to a drastic reduction in wetted area. However, a stepped hull has many disadvantages in that-it gives a rough ride as the boat drops from the step to the aft bottom portion as the step clears the crest of a wave and the provision of a step, of any vertical extent, tends to weaken the hull at that point and requires considerably stronger construction than would otherwise be required. Further, a boat hull provided with a step of any appreciable vertical extent cannot be readily unloaded from a trailer nor can it be readily backed and maneuvered while moving in reverse.

Accordingly, the main object of this invention is to provide a modified stepped hull including a slightly rearwardly and upwardly inclined portion in lieu of a full depth step with the forward end of the rearwardly and upwardly inclined portion or ramp terminating in a step of minimum vertical height sufficient only to break the suction between the water and the aft portions of the bottom surfaces of the hull disposed rearwardly of the step. By this type of construction; a boat hull may be readily unloaded from a trailer, backed and readily maneuvered while moving in reverse. Further, by providing an inclined ramp terminating forwardly in a step of minimum vertical height in lieu of a full height vertical step, the hull may be more readily constructed by conventional means and does not drop as the step clears the crest of a wave.

Another object of this invention, in accordance with the immediately preceding object, is to provide a hull including a modified ll-configuration with opposite side longitudinally extending coves extending throughout the forward portion of the hull bottom surfaces defined by depending chines extending along the opposite side marginal portions of the forward bottom surfaces of the hull.

A final object of this invention to be specifically enumerated herein is to provide a hull construction in accordance with the precedingobjects which will conform to conventional forms of manufacture, be of simple construction and smooth in operation so as to provide a device that will be economically feasible, long lasting and easy to maneuver.

These together with other objects and advantages which will become subsequently apparent reside in the details of construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawings forming a part hereof, wherein like numerals refer to like parts throughout, and in which:

FlG. l is a top plan view of a hull constructed in accordance with the present invention;

H6. 2 is a side elevational view of the assemblage illustrated in H0. l;

FIG. 3 is a bottom plan view of the assemblage illustrated in N68. l and 2;

H6. 4 is a front elevational view of the hull construction;

FIG. 5 is a rear elevational view of the hull construction;

PKG. 6 is an enlarged fragmentary side elevational view illustrating the minimal step defined at the juncture between the forward end of the rearwardly and upwardly inclined ramp surface and the rear end portion of the forward bottom surfaces; and

H0. '7 is a fragmentary enlarged transverse vertical sectional view illustrating the manner in which a decking panel may be secured to the upper edges of the sides of the hull construction after the interior of the hull construction has been filled with flotation.

Referring now more specifically to the drawings, the numeral ll) generally designates the hull construction of the instant invention which may be seen to include a pair of rightand left-hand sides l2 curving toward each other at their forward ends in order to form a bow l4 and joined together at their rear ends by means of a transom l6. Longitudinally extending bottom surfaces of panel means lb extend between the lower marginal edge portions of the sides 12 and a decking panel 20 is secured between the upper marginal edge portions of the sides 12 and the upper marginal edge portion of the transom 16.

The hull construction 10 may include any suitable longitudinal internal bracing members 22 and a transom reinforcing member 24, if desired. Further, an internal bulkhead may be provided if desired approximately halfway between amidships and the bow M.

The bottom panel means 18 includes a forward bottom section 28, an intermediate bottom section 30, and a rear bottom section 32. The forward section 28 extends generally horizontally forward from generally amidships and curves forwardly and upwardly at its forward end to the bow 14. The intermediate section 30 is inclined rearwardly and upwardly away from the rear extremities of the forward section 28 and the rear section 32 extends generally horizontally rearwardly from the rear terminal end portions of the intermediate section 30.

From FIG. 5 of the drawings it may be seen that the rear section 32 includes a pair of oppositely upwardly and outwardly inclined side sections 34 and '36 and that the intermediate section 30 includes a pair of opposite upwardly and outwardly inclined opposite side sections 38 and 40. Finally, the front section 28 includes a pair of opposite upwardly and outwardly inclined sections 42 and 44 which terminate outwardly in coves 46 and d8 defined by downwardly and outwardly inclined chines 50 and 52.

From FIG. 4 of the drawings it may be appreciated that the sections 42 and 44 taper in width as they curve upwardly toward the bow 14 and that the coves 46 and 43 as well as the chines 50 and 52 curve toward each other as they curve upwardly toward the how 14 where they emerge.

The coves 46 and 48 tend to make the bow l4 climb slightly out of the water as speed is increased and it will be noted that the upper extremities of the coves 46 and 48 are radiused, at least slightly. Further, the junctures between the sides 12 and the chines 50 and 52 are rounded and the junctures between the sections 34 and 36, between the sections 38 and 40 and between the sections 42 and 44 are also rounded.

With attention now invited more specifically to FIG. 6 of the drawings, it will be noted that the forward end of the intermediate rearwardly and upwardly inclined ramp section 30 terminates in a rounded step 54 which is of minimum height, approximately one-eighth to one-half inch in vertical extent.

in actuality, test models have operated successfully with the step 54 being only one thirty-second of an inch in vertical extent. However, such a small step might readily be worn off or painted over as a result of normal use and be rendered inoperative.

The step 54 has a radius of curvature of approximately 1% inches and a line tangent to its forward extremity is inclined approximately 45 relative to the rear end portions of the section 28. Further, the section 30 is inclined rearwardly and upwardly less than 15.

The rear generally horizontal portions of the forward section 28 are inclined forwardly and upwardly less then 5 relative to a line drawn between point A and point B in MG. 2 and the planing surfaces defined by the rear section 32 are inclined forwardly and upwardly less than 5 relative to line AB. Further, the width of the ramp or section 30 is at least onetenth of the maximum width of the bottom surfaces of the hull construction lit.

in operation, the utilization of section or ramp 30 eliminates the provision of a step of considerable vertical extent and thus the attendant weakening of the hull in this area. Further, the ramp 3t) enables the hull construction ll) to slide easily off a trailer or from a beach and to operate well in reverse and slide, rather than drop off, the crest of a wave giving a smoother ride. Testing has shown that if the angle of the ramp 30, less than 15 relative to the line AB, is small, water passing beneath the hull construction will tend to follow the bottom surfaces and flow up the ramp 30 at low and medium speeds causing high drag. However, the provision of the small step 54 enables the suction between the ramp 30 and the water to be broken with the result that the hull construction 10 planes onthe rear bottom surfaces of the section 28 and the rear bottom surfaces of the section 32.

The hull construction 10 may be filled with foam flotation 60 and the upper marginal edges of the sides 12 may curve outwardly as at 62 in order to form horizontal flange portions 64. to which the corresponding marginal edges 66 of the decking panel 20 may be secured by means of suitable fasteners 67, see FIG. 7. Further a step defining a right angle at the rear end of the forward section 28 would be the most desirable shape of the step 54. However, the hull construction 10 is to be mass produced by molding of Fiberglas, it is necessary that the step 54 be radiused, at least to an extent enabling free removal of the hull construction 10 from its mold during manufacture.

The foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.

lclaim:

1. A boat hull construction including longitudinally extending bottom surfaces, said bottom surfaces including a forward section extending generally horizontally forward from generally amidships and curving forwardly and upwardly at its forward end, an intermediate section inclined rearwardly and upwardly from the rear end of said forward section at an angle less than i5, and a generally horizontally disposed rear section extending rearwardly from the rear end of said intermediate section, a vertically short minimum height step defined between the front and rear ends of said intermediate and forward sections, respectively, with the rear end of said forward section disposed below the elevation of the forward end of said intermediate section.

2. The combination of claim 1 wherein said rear section includes a pair of opposite side upwardly and outwardly inclined surfaces.

3. The combination of claim 1 wherein said intermediate section includes a pair of opposite side rearwardly and upwardly inclined surfaces which are also upwardly and outwardly inclined.

4. The combination of claim 1 wherein said forward section includes a pair of opposite side upwardly and outwardly inclined surfaces.

5. The combination of claim 1 wherein said forward section includes a pair of opposite side upwardly and outwardly inclined surfaces terminating outwardly in downwardly and outwardly inclined chines, said forward section inclined surfaces and said chines defining downwardly opening coves extending longitudinally along the opposite sides of said forward section.

6. A boat hull construction including longitudinally extending bottom surfaces, said bottom surfaces including a forward section extending generally horizontally forward from generally amidships and curving forwardly and upwardly at its forward end, an intermediate section inclined rearwardly and upwardly from the rear end of said forward section, and a generally horizontally disposed rear section extending rearwardly from the rear end of said intermediate section, a vertically short step defined between the front and rear ends of said intermediate and forward sections, respectively, with the rear end of said forward section disposed below the elevation of the forward end of said intermediate section, said forward section surfaces, throughout the generally horizontal rear portions thereof, being inclined forwardly and upwardly less than 5 relative to a straight line extending between the central rear terminus of said rear section and the central rear terminus of said forward section, said rear section surfaces being also inclined forwardly and upwardly less than 5 relative to said straight line.

7. The combination of claim 1 which said step is between A; inch and lunch in vertical extent. 

1. A boat hull construction including longitudinally extending bottom surfaces, said bottom surfaces including a forward section extending generally horizontally forward from generally amidships and curving forwardly and upwardly at its forward end, an intermediate section inclined rearwardly and upwardly from the rear end of said forward section at an angle less than 15*, and a generally horizontally disposed rear section extending rearwardly from the rear end of said intermediate section, a vertically short minimum height step defined between the front and rear ends of said intermediate and forward sections, respectively, with the rear end of said forward section disposed below the elevation of the forward end of said intermediate section.
 2. The combination of claim 1 wherein said rear section includes a pair of opposite side upwardly and outwardly inclined surfaces.
 3. The combination of claim 1 wherein said intermediate section includes a pair of opposite side rearwardly and upwardly inclined surfaces which are also upwardly and outwardly inclined.
 4. The combination of claim 1 wherein said forward section includes a pair of opposite side upwardly and outwardly inclined surfaces.
 5. The combination of claim 1 wherein said forward section includes a pair of opposite side upwardly and outwardly inclined surfaces terminating outwardly in downwardly and outwardly inclined chines, said forward section inclined surfaces and said chines defining downwardly opening coves extending longitudinally along the opposite sides of said forward section.
 6. A boat hull construction including longitudinally extending bottom surfaces, said bottom surfaces including a forward section extending generally horizontally forward from generally amidships and curving forwardly and upwardly at its forward end, an intermediate section inclined rearwardly and upwardly from the rear end of said forward section, and a generally horizontally disposed rear section extending rearwardly from the rear end of said intermediate section, a vertically short step defined between the front and rear ends of said intermediate and forward sections, respectively, with the rear end of said forward section disposed below the elevation of the forward end of said intermediate section, said forward section surfaces, throughout the generally horizontal rear portions thereof, being inclined forwardly and upwardly less than 5* relative to a straight line extending between the central rear terminus of said rear section and the central rear terminus of said forward section, said rear section surfaces being also inclined forwardly and upwardly less than 5* relative to said straight line.
 7. The combination of claim 1 which said step is between 1/8 inch and 1/2 inch in vertical extent. 